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duong thang d cach deu A,B thi d thuoc mat phang trung truc cua AB.Do d thoc (P) \(
\rightarrow d\in (P)\bigcap (Q)
\)
Goi trung diem I\(\left ( 3/2,5/2,1 \right )
\)cua AB;\(\overrightarrow{BA}\left ( 3,1,0 \right )\Rightarrow
\)mat phang trung truc cua AB la:\(
\left ( Q\right ):3x+y-7=0
\) co VTPT \(
\overrightarrow{n}(3,1,0)\)
(P) co VTPT \(
\overrightarrow{u}(1,1,1)\)
\(\Rightarrow \overrightarrow{d}=\left[ {\overrightarrow{n}\times \overrightarrow{u}} \right]\Rightarrow
\)ta viet dc duong thang d co VTCP la\(
\overrightarrow{d}\)va di qua diem H(2,1,4) la diem chung cua 2 mat phang (Q) va(P)
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